PREHEAT THE OVEN AND PREPARE THE PAN

1. Preheat the oven to 325°F (165°C).
2. Lightly grease an 8 × 8-inch square metal baking pan, then line it with parchment paper, leaving a slight overhang on each side for easy removal. Set aside.

MAKE THE BROWNIE BATTER

1. Place the cubed butter, chocolate chips, and salt in a heatproof bowl set over a saucepan with 1–2 inches of gently simmering water. Stir frequently until the butter and chocolate are completely melted. Alternatively, you can microwave in 20- second intervals, stirring well after each, until smooth and melted.
2. Remove from the heat and stir in 3/4 cup (222 g) of the Nutella. The mixture does not need to be completely smooth at this stage; set aside.
3. In a separate mixing bowl, add the granulated sugar and eggs. Whisk vigorously for 2–3 minutes, until the mixture lightens in color, thickens slightly, and takes on a creamy texture.
4. Add the vanilla extract along with the melted chocolate mixture and whisk gently until fully combined.
5. Add the gluten-free 1:1 flour and cocoa powder, then fold the batter together using a rubber spatula until no dry streaks remain. The batter will be thick.
6. Transfer the batter to the prepared pan and smooth the top into an even layer. Dollop the remaining 1/4 cup (74 g) of Nutella over the surface, then use a toothpick or skewer to gently swirl it into the batter.

BAKE THE BROWNIES

1. Bake on the center rack for 35–45 minutes, or until the edges are set and a toothpick inserted into the center comes out with moist crumbs or a small amount of batter attached.
2. Place the pan on a wire rack and allow the brownies to cool completely before removing from the pan.

SLICE AND SERVE

1. Use the parchment overhang to lift the brownies from the pan.
2. Slice into squares and serve.